Precession Electron Diffraction

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Atomic positions displaced. Electron diffraction : challenges for structure analysis … electron diffraction data can b
IDENTIFICATION – FINGERPRINTING – SOLVING ab-intio NANOSTRUCTURES BY

PRECESSION ELECTRON DIFFRACTION

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PRECESSION ELECTRON DIFFRACTION NEW analysis technique > 25 articles in 2 years !

Ultramicroscopy Special Issue vol.107 issue 6-7 June 2007

Unknown nanostructures…… HOW analyze them ??

Single crystal > 5 microns X-ray diffraction

Powder X-ray diffraction

TEM microscopy

X- Ray powder diffraction: limitations < 10nm

overlapping

> 1Pm

Nanocrystals : peak broadening

Electron diffraction: advantages Every TEM (electron microscope) may produce ED patterns from individual single nanocrystals

TEM goniometer

ED information: Cell parameter and symmetry determination Measuring intensity values leads to structure determination

Electron diffraction : challenges for structure analysis … electron diffraction data can be strongly distorted by dynamical scattering

Dynamical scattering ( thickness > 10 nm )˫

WRONG MODEL light atoms do not appear Atomic positions displaced

Kinematical scattering (very thin crystals)˫

I (k) = I F (k) I 2 CORRECT MODEL

Solution: Precession Electron Diffraction (Vincent-Midgley)˫ . before precession NO precession Beam precesses about exact zone axis direction; reduces extent of dynamical scattering in on-axis condition.

PRECESSION REFLECTIONS MORE KINEMATICAL ( LIKE X-RAY CASE)

WITH precession

Precession AFTER n of ctio Proje t beam en Incid

Vincent & Midgley Ultramicroscopy 53 (1994) 271, 306

J. Gjønnes et al. Acta Cryst A54 (1998)

Advantages of precession in single exposure data collection

with beam precession, Ewald sphere also precess though the reciprocal space

• More fully recorded reflections • More spots per image • Reduced dynamic effect

SPINNING STAR UNIVERSAL INTERFASE FOR PRECESSION ELECTRON DIFFRACTION FOR ANY TEM

¥

JEOL 200 kv,JEOL 120 KV,2010,2100, 2000, 2010 FEG

¥

FEI Tecnai 30 FEG , Tecnai 12 (120 kv),Tecnai 20 ( 200 kv)˫ , Tecnai 10

¥

Philips EMXXX, CM10, CM20, CM30 , STWIN, UTWIN

Topcon 200 KV (Japan demo facility) ¥

¥

Can be easily installed to any TEM 100- 400 KV (LaB6-FEG)˫ ¥

Zeiss 912 ˫ Hitachi 200 KV

¥Precession is possible for a parallel or convergent beam

¥

Precession spot size ( 5 - 50 nm )˫

Precession angle can vary continuously from 0° to 4°, to observe true crystallographic symmetry variation ¥

Ab-initio structure solution with precession of …… Catalysts ( zeolites)˫ Oxides ( perovskites )˫ Complex oxides (Cs-Nb-O )˫ Minerals Polymers Pharmaceuticals …… Proteins

APPLICATION : FIND TRUE CRYSTAL SYMMETRY – SOLVING CRYSTAL STRUCTURES

[100]

PRECESSION OFF

Garnet cubic Ia3d a=1.2 nm

[100] IDEAL KINEMATICAL

simulation

PRECESSION ON

UVAROVITE Ca3Cr2(SiO4)3

Dynamical interactions due to thickness effects may deform intensities in a way that crystal symmetry cannot be recognized; by applying precession true crystal symmetry can be revealed and dynamical scattering is greatly reduced PRECESSION ED INTENSITIES (PED ) ARE CLOSE TO ( IDEAL ) KINEMATICAL INTENSITIES : WE CAN USE PED TO SOLVE DIRECTLY CRYSTAL STRUCTURES OF NANOCRYSTALS LIKE IN XRAY DIFFRACTION Courtesy M.Gemmi Univ of Milano

Is possible from simple ZOLZ/FOLZ symmetry comparison to deduce

point and space group nanocrystal symmetry

J.P.Mornirolli, JW Steeds Ultramicroscopy 1992, 45 , 219

HOW ?

by simply increasing precession angle , FOLZ /ZOLZ reflections and their relative symmetry becomes visible in ED patterns

PRECESSION OFF

FOLZ

FOLZ

ZOLZ ZOLZ

D D q q

ZOLZ

D q

SiC FOLZ

Space group deterrmination by

reflections

ZOLZ

PRECESSION ELECTRON DIFFRACTION SiC 4H hexagonal

P63mc

Courtesy JP Mornirolli Univ of Lille France

reflections

D q

AUTOMATIC crystal symmetry determination by analysis of ZOLZ @ FOLZ precession patterns

hk1

Precession electron diffraction : ab initio determination of nanostructures TEM crystal experiment

ED intensities collection from several zone axis (ELD – Triple )˫ semi- automatic (off-line)˫

STRUCTURE DETERMINATION (Direct methods)˫ semi-automatic (SIR software)˫ Refinement crystal structure

Electron diffraction intensities are measured automatically ( ELD software )

FROM Image plates Photo film OR CCD camera

1k x 1k 2k x 2k 4k x 4k

8k x 8k

or from electron diffractometer

3D structure solution examples Mauro Gemmi and Stavros Nicolopoulos Structure solution with three-dimensional sets of precessed electron diffraction intensities

Ultramicroscopy, Volume 107, Issues 6-7, June-July 2007, Pages 483-494

Åkermanite

Uvarovite

Structure

Composition

Space Group

Åkermanite Uvarovite

(Ca2MgSi2O7) P-421m Ca3(Al0.4Cr0.6)2Si3O12 I a –3 d

Cations Oxygens 3 3

3 1

Structure solution with precession diffraction: Åkermanite Three-dimensional set of precession electron diffraction intensities obtained merging [1 0 0] [0 0 1] [1 0 1] [1 0 2] zone axes. All atoms found, correctly labelled, = 0.1262 from published coordinates. Atom Ca Si Mg O O O

X(Sir) 0.843 0.648 0.500 0.654 0.567 0.500

Y(Sir) 0.343 0.148 0.500 0.154 0.330 0.000

Z(Sir) 0.486 0.060 0.000 0.801 0.211 0.193

X(Pub) 0.832 0.640 0.000 0.860 0.581 0.000

Y(Pub) 0.332 0.140 0.000 0.640 0.314 0.500

Z(Pub) 0.494 0.065 0.000 0.256 0.217 0.817

Distance 0.12498 0.09056 0.00000 0.32573 0.16526 0.05064

PRECESSION RESOLUTION - X RAY RESOLUTION SYNCHROTRON X RAY

0.12 nm CONVENTIONAL X- RAY

0.05 nm

> 17.000

REFLECTIONS OBSERVED

0.19 nm UTWIN

0.24 nm STWIN

TVIPS F224 HD

Weirich et al Ultramicroscopy 2006 Cs-Nb-W-0 oxide , ALL heavy atoms revealed by precession diffraction

PRECESSION OFF

PRECESSION ON

simulation

PRECESSION on POLYMERS Melon ([C6N7(NH2)(NH)]n, plane group p2gg a = 16.7 Å, b = 12.4 Å, g = 90°, Z = 4

Courtesy M. Doblinger Univ of Munich Germany

Precession from pharmaceutical nanocrystals

PED patterns in pharmaceutical crystals allow to work with close or with ZA oriented patterns , revealing true crystal symmetry and kinematical intensities good for structure determinations

amoxycillin penicillin G-potassium 0.9Å

1.1Å

1.1 Å

without precession

without precession

Samples C.Giacovazzo CNR Bari

with precession

Courtesy JP Abrahams, D.Georguieva Univ Leiden

Precession ED from 3d protein lysozyme nanocrystals

protein crystals show much better quality PED patterns ( suitable for symmetry and structure determination ) than conventional SAED patterns

2.7Å 2.7Å

Courtesy JP Abrahams, D.Georguieva Univ Leiden

ZEOLITES ITQ-29 ab initio structure determination

no PRECESION

with PRECESION

Is possible to determine complete structure from a single ED obtained at 100 kV

Different methods: direct methods (FOCUS), maximun entropy (MICE), real space (FOX), ...

Zeolita A

Ihkl proportional to |Fhkl|2 Pm3m, a=11.87Å

ZEOLITES : Ab initio determination of MCM-22 (ITQ-1) zeolite framework

PRECESSION ON

IDEAL KINEMATICAL

3D frameworks can be revealed by collecting and combining quasikinematical precession electron diffraction intensities from different zone axis to one 3D electron diffraction data set ( image courtesy Douglas Dorset USA)˫

PRECESSION ON

old TEM…… works well !

SOLUTION: ENHANCE NEW TEM

> 36 installations world-wide OR UPGRADE OLDER TEM TO POWERFUL STRUCTURE DETERMINATION

NanoMEGAS INSTALLATIONS WORLDWIDE PHILIPS TEM CM30 , CM 20 , CM12, CM10 , EM 400 JEOL TEM JEOL 2000, JEOL 2100, JEOL 2010, JEOL 2010 FEG , JEOL 1400 FEI TEM TECNAI 10, TECNAI 12, TECNAI 20 , TECNAI 20 FEG STEM, TEM 30 FEG STEM ZEISS TEM 912 OMEGA FILTER

DEMO SITES PARIS Philips CM12 JAPAN Tokyo Topcon EM 002B 200 kv

TVIPS Munich JEOL 2010, Tecnai12

TOTAL > 36 INSTALLATIONS

1st precession electron diffraction user meeting

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NEW tools for your TEM… EDS TEM EELS

PRECESSION UNIT

STEM

CCD

ELECTRON DIFFRACTOMETER

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